Valve coupling structure of reciprocating compressor and coupling method thereof

ABSTRACT

A valve coupling structure of a reciprocating compressor and a coupling method thereof, including a piston ( 20 ) which performs a linear reciprocating movement inside a cylinder ( 10 ) by having a gas flow path (F) in which gas flows, a valve ( 40 ) which is positioned to be contacted on an end surface of the piston ( 20 ) to open and close the gas flow path (F) of the piston ( 20 ), and a diffusion bonding portion (D) which is diffused and combined to a part of an end surface of the piston ( 20 ) and the contact surface of the valve ( 40 ) which is contacted on an end surface of the piston ( 20 ) by movement of atoms or movement among atoms which form the valve ( 40 ) using an energy source of the outside can make coupling state of the piston ( 20 ) which performs linear reciprocating movement inside the cylinder ( 10 ) and valve ( 40 ) more firm.

TECHNICAL FIELD

[0001] The present invention relates to a reciprocating compressor and particularly, to a valve coupling structure of a reciprocating compressor and a coupling method thereof, capable of preventing deformation and damage of a suction valve which continuously opens/closes a gas flow path and minimizing a dead volume of a compression space.

BACKGROUND ART

[0002] Generally, a compressor is an instrument for compressing fluid such as air and refrigerant gas. The compressor generally includes a motor unit installed in a closing case, for generating a driving force and a compressing unit for sucking and compressing refrigerant gas by receiving the driving force of the above motor unit and is classified into a rotary compressor, reciprocating compressor and a scroll compressor according to the structure of the compressing unit.

[0003] The reciprocating compressor among them is a compressor in which a driving force of the motor unit is transmitted to the piston and the piston sucks, compresses and discharges refrigerant gas performing linear reciprocating movement in a cylinder.

[0004]FIGS. 1 and 2 show an embodiment of the compressing unit of the reciprocating compressor and the compressing unit of the reciprocating compressor includes a cylinder 10 where a through hole 11 forming a compression space P inside the hole is formed, a piston inserted in the through hole 11 of the cylinder 10 enabling linear reciprocating movement and a discharge valve assembly 30 combined to the end portion of the cylinder 10 to cover the through hole 11.

[0005] The piston 20 has a head portion 22 at one side of the body portion 21 having a certain length and a connection portion 23 lengthened into a certain area at the other side of the body portion 21. In the body portion 21, a first gas passage 24 having a certain depth is formed at the other side of the body portion 21 and in the body and head portions 21 and 22, a gas flow path F is formed so that refrigerant can flow.

[0006] A suction valve 40 for opening and closing the second gas passage 25 is positioned in the head portion 22 and the connection portion 23 of the piston is 20 is connected into the motor unit (not shown) for generating a driving force.

[0007] On the other hand, the suction valve 40 is composed of a thin plate in a round form and has a cutting hole 41 is positioned inside a circular sheet. The circular sheet is divided into a fixing portion 42 and opening and closing portion 43 by the cutting hole 41 by the cuffing hole.

[0008] The suction valve 40 is fixed-combined to the head portion 22 of the piston 20 having a fixing bolt 50 penetrated by the fixing portion 42 of the suction valve 40 under the condition that the suction valve 40 is contacted on the end surface of the head portion 22 of the piston 20.

[0009] Also, the discharge valve assembly 30 includes a discharge cover 31 combined to cover the end portion of the cylinder 10, a discharge valve 32 inserted in the discharge cover 30, for opening and closing the compression space P formed by the through hole 11 and piston 20 of the cylinder 10 and a valve spring 33 for elastically supporting the discharge valve 32.

[0010] Hereinafter, the operation of the compression unit of the conventional compressor will be described as follows.

[0011] First, a driving force of the motor unit is transmitted to the piston 20 and the piston 20 performs a linear reciprocating movement in the cylinder 10.

[0012] In the process, as shown in FIG. 3, when the piston 20 moves to the direction of a lower dead point a, the discharge valve 32 is contacted on the end portion of the cylinder 10 by pressure difference and blocks the compression space P. At the same time, the suction valve 40 combined to the piston 20 is bent and refrigerant gas is sucked into the compression space P of the cylinder 10 formed in the cylinder 10 through the gas flow path F formed inside the piston 20.

[0013] When the piston 20 reaches to the lower dead point (a) and then moves to the upper dead point (b), the suction valve 40 returns to the original state and the gas flow path F of the piston 20 is closed. Accordingly, the refrigerant gas sucked to the compression space P of the cylinder 10 is compressed and when the gas reaches to the upper dead point (b), the discharge valve 32 is opened. Then, the refrigerant gas is discharged. As the above process is repeated continuously, refrigerant gas is compressed.

[0014] However, in the above structure, since the suction valve 40 formed as a sheet is fixed-combined by the fixing bolt 50, slip rotation of the suction valve 40 is occurred in the process that the opening/closing of the suction valve 40 was repeatedly performed as the piston performs a linear reciprocating movement. Then, the compressor could not perform compression function as the suction valve 40 missed from the gas flow path F penetrated-formed in the head portion 22 and since a through hole 44 for coupling the fixing volt 50 in the suction valve 40 is formed, the structural strength of the compressor was degraded.

[0015] A dead volume is generated since the head portion of the fixing bolt 50 is positioned in a shape that it is protruded into the compression space P, thus to decline compressing efficiency. Also, position sensing of the upper dead center (b) and lower dead center a of the piston 20 is difficult by the protruded head portion of the fixing bolt 50 and accordingly, controlling of a stroke of reciprocating movement of the piston 20 became difficult.

[0016] As a structure to solve the above problem, a structure for combining the fixing portion 42 to the end surface of the head portion 22 of the piston by welding was suggested, but as characteristic of materials of the suction valve 40 is changed by heat deformation due to welding heat in welding the suction valve 40 to the head portion of the piston 20 and opening and closing of the suction valve 40 is continuously performed, fatigue fracture was occurred centering a welding point.

DISCLOSURE OF THE INVENTION

[0017] Therefore, an object of the present invention is to provide a valve coupling structure of a reciprocating compressor and a coupling method thereof, capable of preventing deformation and damage of a suction valve which continuously opens/closes a gas flow path and minimizing a dead volume of a compression space.

[0018] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a valve coupling structure of a reciprocating compressor, including a piston which performs a linear reciprocating movement inside a cylinder with having a gas flow path in which gas flows, a valve which is positioned to be contacted on an end surface of the piston to open and close the gas flow path of the piston, and a diffusion bonding portion which is diffused and combined to a part of an end surface of the piston and the contact surface of the valve which is contacted on an end surface of the piston by movement of atoms or movement among atoms, which form the valve by using an energy source of the outside.

[0019] Also, there is provided a valve coupling method of a reciprocating compressor, comprising the steps of processing a contact surface of an end surface of a piston and a valve which is contacted with the end surface of the piston, contacting the contact surface of the valve on the end surface of the piston, performing first pressurization so that the surface of the piston and surface of the valve are permanently deformed in a pressurization part of the contact surface of the end surface of the piston and the valve by pressurizing a part of the contact surface of the end surface of the piston and the valve which is contacted on the end surface of the piston, performing second pressurization so that the atoms of the above materials are moved and coupled as the surface of the piston and the surfaces of the valve are permanently deformed and removing a pressure added to the piston and valve.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a cross-sectional view showing a compression unit of a conventional reciprocating compressor;

[0021]FIG. 2 is a exploded perspective view showing an embodiment of a suction valve coupling structure of the conventional reciprocating compressor;

[0022]FIG. 3 is a cross-sectional view showing the operational state of the compression unit of the conventional reciprocating compressor;

[0023]FIG. 4 is a cross-sectional view showing a compression unit of a reciprocating compressor having a suction valve coupling structure of a reciprocating compressor of the present invention;

[0024]FIG. 5 is a cross-sectional view showing another embodiment of the reciprocating compressor in accordance with the present invention;

[0025]FIG. 6 is a flow chart showing a suction valve coupling method of the reciprocating compressor in accordance with the present invention;

[0026]FIG. 7 is an enlarged view illustrating a changing process of the internal structure of a contact surface on which the suction valve and the piston head are contacted by the suction valve coupling structure of the reciprocating compressor in-accordance with the present invention and the method thereof; and

[0027]FIG. 8 is a cross-sectional view showing an operation state of the suction valve coupling structure of the reciprocating compressor in accordance with the present invention.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

[0028] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[0029] Hereinafter, the valve coupling structure of the reciprocating compressor and the coupling method thereof in accordance with the present invention will be described with reference to the embodiment shown in the accompanied drawings.

[0030]FIG. 4 is a cross-sectional view showing a compression unit of the reciprocating compressor having a suction valve coupling structure of the reciprocating compressor of the present invention. As shown in the drawing, the compression unit of the reciprocating compressor includes a cylinder 10 where a through hole 11 forming a compression space P therein is formed, a piston 20 which is inserted in the through hole 11 of the cylinder 10 so that it can perform a linear movement, a discharge valve assembly 30 combined to the end portion of the cylinder 10 to cover the through hole 1 1 and a suction valve 40 which is combined to an end surface of the piston 20 by the movement of atoms, for opening and closing the gas flow path F which is penetrated and formed inside the piston 20.

[0031] The piston 20 includes a head portion 22 at a side of a body portion 21 having a certain length, a connection portion 23 lengthened at the other side of the body portion 21 having a certain area and a gas flowing passage F penetrated to flow refrigerant gas in the body portion 21 and head portion 22. The connection portion 23 of the piston 20 is connected to a motor unit (not shown) for generating a driving force.

[0032] A suction valve 40 is combined with the head portion 22 of the piston 20 by the diffusion bonding method for coupling the suction valve 40 for opening is and closing the gas flow path F by movement of atoms.

[0033] That is, the diffusion bonding method means a method for coupling two pressurized and attached under a predetermined temperature condition without melting two parts moving atoms by natural and compulsory diffusion (solid state diffusion) among metal atoms.

[0034] To cause diffusion among the metal, a predetermined temperature condition is made using a predetermined outer energy source. In the present invention, the temperature is set as a low temperature lower than about 450° C.

[0035] In the suction valve 40, a cutting groove (shown in FIG. 2) 41 is positioned inside a circular sheet and the circular sheet is divided into a fixing portion 42 by the cutting groove 41.

[0036] That is, in the suction valve 40, a diffusion boding portion D which is diffused and bonded so that there is no heat-affected portion by movement of atoms which compose the fixing portion 42 of the suction valve 40 and end surface of the piston head portion 22 is formed under the condition that the end surfaces of the head portions of the fixing portion 42 and piston 20.

[0037] The diffusion bonding portion D corresponds to some regions of the fixing portion 42 of the suction valve 40 and an end surface of the piston head portion 22 which is contacted with the region.

[0038] Hereinafter, another embodiment of the suction valve coupling structure of the reciprocating in accordance with the present invention will be described.

[0039] That is, as shown in FIG. 5, an insertion groove 24 having a predetermined area and depth is formed of an end surface of the head portion is 22 of the piston which is contacted with the suction valve 40 and an insertion material 60 which is formed according to the shape of the insertion groove 24 is inserted, fixed and attached into the insertion groove 24. In addition, a diffusion boding portion D which is diffused and attached so that there is no heat-affected part caused by movement of atoms composing the suction valve 40 and atoms composing the insertion material 60.

[0040] The diffusion bonding portion D corresponds to some regions of the fixing portion 42 of the suction valve 40 and some regions of the insertion material which are contacted with the region.

[0041] The insertion material 60 is made of a material having good adhesiveness and it is desirable that the insertion material is made of a material having a similar atomic structure as the suction valve 40 and the insertion material 60 is inserted in the insertion groove 24 of the piston 20 and is fixed and combined by brazing welding.

[0042] It is desirable that the material of the suction valve 40 belong to stainless group.

[0043] On the other hand, the discharge valve assembly 30 includes a discharge cover 31 which is coupled to cover the through hole 11 of the cylinder 10, a discharge valve 32 which is inserted in the discharge cover 31, for opening and closing the compression space P which is formed by the through hole 11 of the cylinder 10 and the piston 20, and a valve spring 33 for elastically supporting the discharge valve 32.

[0044] Hereinafter, the suction valve coupling method of the reciprocating compression of the present invention will be described.

[0045] As shown in FIG. 6, the coupling method includes the steps of processing the end surface of the piston in which the suction valve 40 is positioned, that is, of the piston head portion 22, processing the contact surface of the suction valve 40 which is contacted on the end surface of the piston head portion 22, and contacting the contact surface of the suction valve 40 on the end surface of the piston 20.

[0046] Also, the method includes the steps of performing first pressurization so that the surface of the piston 20 and surface of the valve 40 are permanently deformed in a pressurization part of the end surface of the piston 20 and the valve 40 by pressurizing a part of the valve 40 which is contacted on the end surface of the piston 20, and performing second pressurization so that the atoms of the above materials are moved and coupled as the surface of the piston 20 and the surfaces of the valve 40 are permanently deformed in a pressurization part of the end surface of the piston 20 and the valve 40 by pressurizing a part of the valve 40.

[0047] As the first and second pressurizing steps are processed, a changing process of the internal structure of a contact surface on which the end surface of the piston 20 and contact surface of the suction valve 40 are coupled will be described with reference to FIG. 7.

[0048] At this time, combination of the piston 20 and suction valve 40 is not occurred by heat, and accordingly, heat-deformed part is not generated.

[0049] Then, the step of removing pressure added to the piston 20 and suction valve 40 is processed.

[0050] On the other hand, in case the insertion material 60 is inserted in the piston 20, the suction valve 40 couples with the insertion material 60 which is inserted and coupled with the piston 20.

[0051] Hereinafter, the operational effect of the valve coupling structure of the reciprocating compressor and the coupling method will be described as follows.

[0052] Firstly, as shown in FIG. 8, in the operation of the compression unit of the reciprocating compressor, when the piston 20 performs linear reciprocating movement inside the cylinder 10, that is, between the upper dead point (b) and lower dead point (a) of the compression space P, as bending and spreading of the suction valve 40 combined to the piston 20 are repeated, and the gas flow path F of the piston 20 is opened and closed, refrigerant gas is sucked to the compression space P of the cylinder 10 through the gas flow path F of the piston 20, compressed and discharged by opening and closing operation of the discharge valve 32 which composes the discharge valve assembly 30. The above process is repeated.

[0053] Since combination of the piston 10 and suction valve 40 is conducted by movement of atoms which composes the piston 20 and suction valve 40, the coupling state becomes solid and heat deformation can be prevented, thus to prevent damage by fatigue in repeatedly moving the suction valve 40 and prevent rotation of the suction valve 40 can be prevented.

[0054] Also, the suction valve 40 is fixed and combined to the piston 20 by coupling caused by movement of atoms, and accordingly, the surface which is positioned in the compression space P is formed as a flat plate. Therefore, dead volume generated by the head portion of the fixing bolt 50 can be removed in combining with the fixing bolt 50 as conventionally, thus to increase the volume of the compression space P and easily control stroke of the piston 20 as position sending of the stroke of the piston 20 is eased.

[0055] With the valve coupling structure of the reciprocating compressor and coupling method thereof, coupling state of the piston which performs linear reciprocating movement inside the cylinder and the valve can become more firm. Since heat deformation can be excluded, damage by fatigue in case of repeated movement of the suction valve can be controlled, and the life span of the parts can be lengthened as the rotation movement of the suction valve can be prevented. Also, since opening and closing of the gas flow path can be performed exactly, dead volume can be minimized and compression performance can be improved as control of stroke can be easily conducted.

[0056] At the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, if should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be constructed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalence of such meets and bounds are therefore intended to be embraced by appended claims. 

1. A valve coupling structure of a reciprocating compressor, comprising: a piston which performs a linear reciprocating movement inside a cylinder with having a gas flow path in which gas flows; a valve which is positioned to be contacted on an end surface of the piston to open and close the gas flow path of the piston; and a diffusion bonding portion which is diffused and combined to a part of an end surface of the piston and the contact surface of the valve which is contacted on an end surface of the,!piston by movement of atoms or movement among atoms, which form the valve by using an energy source of the outside.
 2. The structure of claim 1, wherein the valve is made of stainless is material.
 3. The structure of claim 1, wherein insertion material having a similar atomic structure as the valve is inserted and combined being fixed on an end surface of the piston on which the valve is contacted.
 4. The structure of claim 3, wherein the piston and insertion material are coupled each other by brazing welding.
 5. The structure of claim 3, wherein the valve is made of stainless material.
 6. The structure of claim 1, wherein the energy source is formed by using a predetermined resistance heat generated by electrifying a current between two contact surfaces.
 7. The structure of claim 6, wherein the predetermined resistance heat is lower than 450° C.
 8. A valve coupling method of a reciprocating compressor, comprising the steps of: processing a contact surface of an end surface of a piston and a valve which is contacted with the end surface of the piston; contacting the contact surface of the valve on the end surface of the piston; performing first pressurization so that the surface of the piston and surface of the valve are permanently deformed in a pressurization part of the contact surface of the end surface of the piston and the valve by pressurizing a part of the contact surface of the end surface of the piston and the valve which is contacted on the end surface of the piston; performing second pressurization so that the atoms of the above materials are moved and coupled as the surface of the piston and the surfaces of the valve are permanently deformed; and removing the pressure added to the piston and valve. 